The present invention relates to a golf apparatus, and more particularly to a device which simulates the response of natural turf to the impact of a golf club head during a golf swing.
One of the keys to becoming a successful golfer is to consistently and frequently practice the many skills necessary in the game. These include, among others, the drive, the wedge shot, and the chip shot. Each of these facets of golf has its own technique for practicing and improving upon one's skill level.
One such technique involves the repetitive hitting of a golf ball, whether in the home back yard or at a commercial driving range, to practice the basic golf swing using real golf balls and clubs in an accepted manner. One problem with this practice is that, if the ball is hit directly off the ground or even off of a tee, the turf surrounding the practice area may quickly become worn and unsightly. This is especially true in the case of iron shots because a properly executed iron shot will often cause the removal of a small patch of turf known as a divot. To remedy this, the golfer must either retrieve each divot and tamp it back in its original place, which is very time-consuming, or the golfer can continue to hit off of the bare dirt spots on the ground. However, a hit off of barren turf would not provide a natural response to the impact of the club head, and therefore one would not obtain the proper feel during the swing nor would the golf ball travel in a trajectory which is properly indicative of the quality of the swing.
Historically, a golf tee mat has been provided to combat this problem. Such mats are typically made out of a rubber-containing material, or with artificial turf. These mats provide a consistent surface from which to hit the ball, but the surface does not simulate the response of natural turf to an executed golf swing. A correctly executed iron shot, for example, results in the arc described by the club head having its lowest point forward of, and below the rest position of the ball. Normally, this would result in a divot being taken out of the turf by the club head after it has struck the ball. During practice, it would be preferable to hit down into a point immediately in front of the ball, as one would do on natural turf, with the resulting divot occurring during the follow-through of the swing. Because of the unyielding nature of the known practice mats, a golfer is prevented from taking such a natural swing. An attempt to execute this swing can result in the club head catching in the mat and either stopping abruptly, bouncing up, or roaring the mat. The golfer, in attempting to avoid hitting the mat, must make an unnatural adjustment to his swing. This adjustment usually consists of an attempt to sweep the club head across the top of the mat to hit the ball cleanly, yet not hit the mat. This required adjustment is counter-productive to a practice session wherein the golfer would prefer to work on problems associated with his golf swing, rather than problems associated with driving range mats.
Various solutions to these problems have been previously proposed. For example, in U.S. Pat. No. 3,423,096 to Tone, the basic structure of the device is a spring-mounted rigid platform containing a grass-simulating upper surface. When the device is struck by a golf club head during a correctly executed swing, it is capable of deflecting only downward. The ball support surface cannot move horizontally. When a golf club head is impacted against the Tone mat with a velocity that is more horizontal than vertical, the device will only partially correct those problems associated with the traditional golf tee mats.
Another proposed solution is the device described in U.S. Pat. No. 3,712,628 to Boss, Jr., which includes a rigid housing containing horizontally mounted rollers which support an endless belt having grass simulating bristles on its outer surface. A padded platform beneath the upper portion of the belt is mounted so as to pivot about one end and is held against the inner surface of the belt by an elastic supporting member at the other end. The rollers are designed to minimize their resistance to acceleration resulting from the tangential forces imparted by the belt. The uppermost surface of the padded platform is made smooth to minimize friction between the belt and pad allowing translation of the belt across the platform following impact of the golf club head. As the golf club head strikes the belt, the vertical energy component is transferred from the belt to the platform and then to the elastic supporting member which yields, permitting the platform to pivot downwardly. The belt simultaneously translates forwardly as it moves about the rollers due to the horizontal energy component transmitted to it by the club head. The combined downward and forward deflections of the belt momentarily forms a pocket in the belt simulating that left by a removed divot.
One disadvantage associated with such prior art devices is that they are too forgiving of certain types of bad golf swings, particularly one known as a "fat shot," and therefore do not provide feedback to the golfer that his swing was poorly executed. A "fat shot" is one in which the club head hits downwardly toward the ball at approximately the correct angle but the club head catches the turf before hitting the ball. Consequently, there is a buildup of turf between the ball and the club head which makes the ball travel a lesser distance than it would if the swing were properly executed. The fatter the shot the less distance the ball travels. With a device such as that disclosed in the Boss, Jr. patent, a club head which, for example, impacts the belt an inch behind the ball would cause the belt and platform to pivot downwardly immediately upon contact of the golf club head with the belt and the belt would immediately translate forwardly offering little resistance to the club head, thereby allowing the club head to move easily forward into contact with the ball without simulating the buildup of turf that would occur if such a swing were executed on a natural surface.
Another type of belt and roller type golf device is shown in U.S. Pat. No. 4,875,685 to Ballinger et al.
Thus, a need exists for a golf practice apparatus which more accurately simulates the feel of natural turf, and which provides feedback to the golfer to indicate whether or not the ball has been struck with an accurate swing.